It is known to produce an in-mouth disintegrable dosage form for the delivery of drugs. In fact, patents relating generally to this area date back to the last century. Such tablets have significant advantages over other dosage forms; particularly for those who cannot, or will not, swallow a tablet or capsule. Solid dosage forms are far more convenient than liquids. However, the design of orally disintegrable dosage forms carries with it its own set of unique problems.
Chewable tablets such as, for example, those disclosed in U.S. Pat. No. 5,225,197 to Bolt, can be provided. However, such dosage forms often provide inadequate taste-masking of bad tasting medicaments. Chewable formulations are also often incompatible with, for example, delicate microparticles or time-released microparticles. The compressive force used in forming tablets and/or during chewing will often rupture such structures either exposing the patient to the objectionable taste of the material contained therein, or interfering with the structural integrity of the encapsulant and thereby altering its drug delivery profile.
Non-chewable dosage forms have also been tried. For example, Cima Labs has produced oral dosage forms including microparticles and effervescents which rapidly disintegrate in the mouth and provide adequate taste-masking. See Wehling et al., U.S. Pat. No. 5,178,878. Zydis, on the other hand, produces a rapidly dissolvable, freeze-dried, sugar matrix to produce a rapidly dissolving tablet. While these dosage forms are effective, they provide significant problems in terms of production, storage, transport and during consumer usage. They are also significantly more costly to produce.
According to U.S. Pharmacopoeia No. 23, 1995, Chap. 1216 entitled "Tablet Friability," the text of which is hereby incorporated by reference, effervescent tablets and chewable tablets often have different specifications as far as friability, when compared to normal tablets. These tablets normally require special packaging. That, however, is a great understatement.
The Zydis tablets, for example, are so fragile that the matrix material must be formed by freeze-drying in an individual tablet-sized container. While the use of an effervescent couple in combination with microparticles as disclosed in Wheling et al. does overcome the need for such extreme measures, the need to minimize in-mouth disintegration times still require the use of non-traditional packaging and processing methodology. For example, normal conveyors such as vibratory conveyors or bulk hoppers common in the pharmaceutical industry could not be used, as these high-speed, high-volume devices tend to cause damage to the resulting tablets. Similarly, the resulting tablets cannot be stored on a hopper after tableting but before packaging. This can seriously interfere with the processing efficiencies of high-volume presses.
Moreover, the resulting tablets have to be packaged in individual, blister-type packages that are robust enough to avoid tablet breakage. They could not be packaged in a conventional, multi-tablet bottle, individual foil pouches or traditional blister packaging.